The Times did some additional reporting, and alleges the People's Liberation Army targeted at least one company that oversees 60 percent of North America's energy infrastructure:

...the most troubling attack to date, security experts say, was a successful invasion of the Canadian arm of Telvent. The company, now owned by Schneider Electric, designs software that gives oil and gas pipeline companies and power grid operators remote access to valves, switches and security systems.

...

...“This is terrifying because — forget about the country — if someone hired me and told me they wanted to have the offensive capability to take out as many critical systems as possible, I would be going after the vendors and do things like what happened to Telvent,“ Mr. Peterson of Digital Bond said. “It’s the holy grail.”

The Times says the National Electrical Manufacturers Association, a lobbying group that represents companies that make components for power grids, has confirmed it's been attacked but that the hackers did not gain access to their network.